Semiconductor device and method of manufacturing the same

ABSTRACT

A semiconductor device with improved reliability is provided. The semiconductor device is characterized by its embodiments in that sloped portions are formed on connection parts between a pad and a lead-out wiring portion, respectively. This feature suppresses crack formation in a coating area where a part of the pad is covered with a surface protective film.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority from Japanese Patent ApplicationNo. 2014-082804 filed on Apr. 14, 2014, the content of which is herebyincorporated by reference into this application.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a semiconductor device and a method ofmanufacturing the same, and to, for example, a technique appliedeffectively to a semiconductor device having pads and a method ofmanufacturing the same.

BACKGROUND OF THE INVENTION

Japanese Laid-Open Patent Publication No. H8-241909 (patent document 1)describes a technique by which the coating area of a surface protectivefilm that covers a side closest to an edge side of a semiconductor chip,among a plurality of sides making up a pad, is made larger than thecoating area of the surface protective film covering the other sides.

SUMMARY OF THE INVENTION

For example, most of the surface of a pad formed on a semiconductor chipis exposed through an opening provided on a surface protective film. Theedge of the pad, on the other hand, is covered with the surfaceprotective film. Specifically, on the edge of the pad, the surfaceprotective film is so formed as to cover a step that is caused by thethickness of the pad.

A crack may be generated on the surface protective film covering thestep formed on the edge of the pad due to a stress applied upon dicing asemiconductor chip into pieces and a stress applied by a sealing bodysealing the semiconductor chip. The conventional semiconductor device,therefore, should be improved further in view of the necessity ofsuppressing the formation of a crack on the surface protective filmcovering the step formed on the edge of the pad to improve thereliability of the semiconductor device.

Other problems and novel features will be clearly understood byreferring to the descriptive contents of this specification and theaccompanying drawings.

A semiconductor device according to one embodiment includes arectangular semiconductor chip, which has a sloped portion provided in aconnecting part between each of a plurality of pads and a lead-outwiring portion.

According to one embodiment, the reliability of the semiconductor devicecan be improved.

BRIEF DESCRIPTIONS OF THE DRAWINGS

FIG. 1 is a top plan view of a semiconductor device of a QFP packagestructure;

FIG. 2 is a sectional view along an A-A line of FIG. 1;

FIG. 3 illustrates a layout of a semiconductor chip;

FIG. 4 is an enlarged view of a nearby area of a pad formed on thesemiconductor chip;

FIG. 5 is a schematic view of the deformation of the pad;

FIG. 6 is an enlarged plan view of a part of a semiconductor chipaccording to a first embodiment;

FIG. 7 is an enlarged view of a part of a pad not having a slopedportion that is a feature of the first embodiment;

FIG. 8 is an enlarged view of apart of a pad having the sloped portionthat is a feature of the first embodiment;

FIG. 9 is a sectional view along an A-A line of FIG. 6;

FIG. 10 is a schematic view of a configuration of a plurality of padsincluding a gap therebetween according to the related art;

FIG. 11 is a schematic view of a configuration of a plurality of padsincluding a gap therebetween according to the first embodiment;

FIG. 12 is a schematic sectional view along a B-B line of FIG. 6;

FIG. 13 is an enlarged plan view of a part of a semiconductor chipaccording to a modification of the first embodiment;

FIG. 14 is a plan view showing a layout of a semiconductor wafer;

FIG. 15 is a sectional view showing a process of manufacturing asemiconductor device according to the first embodiment;

FIGS. 16A and 16B illustrate a process of manufacturing thesemiconductor device that follows the process of FIG. 15, FIG. 16A beinga plan view of a pad, and FIG. 16B being a sectional view along an A-Aline of FIG. 16A;

FIGS. 17A and 17B illustrate a process of manufacturing thesemiconductor device that follows the process of FIGS. 16A and 16B, FIG.17A being a plan view of a pad, and FIG. 17B being a sectional viewalong an A-A line of FIG. 17A;

FIGS. 18A and 18B illustrate a process of manufacturing thesemiconductor device that follows the process of FIGS. 17A and 17B, FIG.18A being a plan view of a pad, and FIG. 18B being a sectional viewalong an A-A line of FIG. 18A;

FIGS. 19A and 19B illustrate a process of manufacturing thesemiconductor device that follows the process of FIGS. 18A and 18B, FIG.19A being a plan view of a pad, and FIG. 19B being a sectional viewalong an A-A line of FIG. 19A;

FIG. 20 is a diagram of the semiconductor chip after formation of padsthereon, showing a schematic sectional view of the vicinity of aboundary area of an edge side (serving as a boundary in this stage);

FIG. 21 is a flowchart showing a flow of steps of, for example,manufacturing a semiconductor device of a QFP package structure afterthe formation of integrated circuits on a semiconductor wafer;

FIG. 22 is an enlarged view of a part of a semiconductor chip accordingto a second embodiment;

FIG. 23 is an enlarged view of a part of a semiconductor chip accordingto a third embodiment;

FIG. 24 is an enlarged view of a part of a semiconductor chip in a firstmodification according to the third embodiment;

FIG. 25 is an enlarged view of a part of a semiconductor chip in asecond modification according to the third embodiment;

FIG. 26 is an enlarged view of a part of a semiconductor chip accordingto a fourth embodiment;

FIG. 27 is an enlarged view of a part of a semiconductor chip accordingto a modification of the fourth embodiment;

FIG. 28 is a plan view schematically showing a configuration of a padaccording to a fifth embodiment;

FIG. 29 is a plan view schematically showing a configuration of a padaccording to a modification of the fifth embodiment;

FIG. 30 is an enlarged view of a part of a semiconductor chip accordingto a sixth embodiment;

FIG. 31 is an enlarged view of a part of a semiconductor chip accordingto a seventh embodiment; and

FIG. 32 a sectional view showing a gap between the pads according to theseventh embodiment.

DESCRIPTIONS OF THE PREFERRED EMBODIMENTS

In the embodiments described below, the invention will be described in aplurality of sections or embodiments when required as a matter ofconvenience. However, these sections or embodiments are not irrelevantto each other unless otherwise stated, and the one relates to the entireor a part of the other as a modification example, details, or asupplementary explanation thereof.

Also, in the embodiments described below, when referring to the numberof elements (including number of pieces, values, amount, range, and thelike), the number of the elements is not limited to a specific numberunless otherwise stated or except the case where the number isapparently limited to a specific number in principle. The number largeror smaller than the specified number is also applicable.

Further, in the embodiments described below, it goes without saying thatthe components (including element steps) are not always indispensableunless otherwise stated or except the case where the components areapparently indispensable in principle.

Similarly, in the embodiments described below, when the shape of thecomponents, positional relation thereof, and the like are mentioned, thesubstantially approximate and similar shapes and the like are includedtherein unless otherwise stated or except the case where it isconceivable that they are apparently excluded in principle. The samegoes for the numerical value and the range described above.

Also, components having the same function are denoted by the samereference symbols throughout the drawings for describing theembodiments, and the repetitive description thereof is omitted.Moreover, in some drawings for describing in the embodiments, hatchingis used even in a plan view so as to make the drawings easy to see.

First Embodiment Example of Configuration of Semiconductor Device (QFPPackage)

A semiconductor device includes various package structures, such as BGA(Ball Grid Array) and QFP (Quad Flat Package). A technical conceptaccording to a first embodiment can be applied to these packagestructures. Hereinafter, a configuration of a semiconductor device of aQFP package structure will be described as one example.

FIG. 1 is a top plan view of a semiconductor device SA1 of a QFP packagestructure. As shown in FIG. 1, the semiconductor device SA1 is arectangular shape with its upper surface covered with a resin (sealingbody) MR. From four sides defining the outline of the resin MR, outerleads OL project outward.

The internal structure of the semiconductor device SA1 will then bedescribed. FIG. 2 is a sectional view along an A-A line of FIG. 1. Asshown in FIG. 2, the back surface of a chip mounting portion TAB iscovered with the resin MR. A semiconductor chip CHP is mounted on theupper surface of the chip mounting portion TAB, which is separated frominner leads IL1 (lead terminals). Pads PD are formed on the main surfaceof the semiconductor chip CHP. The pads PD formed on the semiconductorchip CHP are connected electrically to the inner leads IL1 via wires W.The semiconductor chip CHP, wires W, and inner leads IL1 are coveredwith the resin MR, and the outer leads OL (lead terminals) integratedwith the inner leads IL1 project out of the resin MR. The outer leads OLprojecting out of the resin MR are molded into a gull-wing shape andhave their surfaces covered with a plating film PF.

The chip mounting portion TAB, inner leads IL1, and outer leads OL aremade of, for example, a 42 alloy that is an alloy of copper, iron, andnickel. The wires W are made of, for example, gold. The semiconductorchip CHP is made of, for example, silicon and compound semiconductor(GaAs, etc.), and has a plurality of semiconductor elements, such asMOSFETs, formed thereon. Above the semiconductor elements, multi-layeredwirings are formed via inter-layer insulating films, and on theuppermost layer of the multi-layered wirings, the pads PD are formed tobe connected to the multi-layered wirings. Therefore, the semiconductorelements formed on the semiconductor chip CHP are connected electricallyto the pads PD via the multi-layered wirings. In other words, thesemiconductor elements formed on the semiconductor chip CHP and themulti-layered wirings jointly form an integrated circuit, and the padsPD function as terminals that connect the integrated circuit to a deviceoutside the semiconductor chip CHP. The pads PD are connected to theinner leads IL1 via the wires W and are therefore connected to the outerleads OL formed integrally with the inner leads IL1. Thus, theintegrated circuit formed on the semiconductor chip CHP is connectedelectrically to a device outside the semiconductor device SA1 via apath: pads PD→wires W→inner leads IL1→outer leads OL→external connectiondevice. It is therefore understood that by inputting electric signals tothe semiconductor chip CHP through the outer leads OL formed on thesemiconductor device SA1, the integrated circuit formed on thesemiconductor chip CHP can be controlled, and that output signals fromthe integrated circuit can be transferred outside through the outerleads OL.

FIG. 3 illustrates a layout of the semiconductor chip CHP. In FIG. 3,the semiconductor chip CHP is, for example, rectangular, and a pluralityof pads PD are arranged along the edge sides ES of the semiconductorchip CHP. Specifically, as shown in FIG. 3, a seal ring SRG is formedinside and along the edge sides ES of the rectangular semiconductor chipCHP. Inside the seal ring SRG, the plurality of pads PD are arrangedalong the edge sides ES of the rectangular semiconductor chip CHP. Ateach of the pads PD, the most part of surface of the pad PD is exposedthrough an opening provided on a surface protective film while the edgeof the pad PD is covered with the surface protective film. This is notshown in FIG. 3.

For example, a crack may be formed on the surface protective filmcovering the edge of the pad due to a stress applied upon dicing thesemiconductor chip CHP into pieces and a stress applied by the resin(sealing body) sealing the semiconductor chip CHP. The conventionalresin-sealed semiconductor device, therefore, should be further improvedin view of the necessity of preventing the formation of a crack on thesurface protective film covering a step formed on the edge of the pad toimprove the reliability of the semiconductor device.

<Semiconductor Device that should be Further Improved>

FIG. 4 is an enlarged view of a nearby area of the pad PD formed on thesemiconductor chip. As shown in FIG. 4, the seal ring SRG is formedinside the edge side ES of the semiconductor chip and the pad PD isformed inside the seal ring SRG. The pad PD is rectangular and has alead-out wiring portion DWU formed integrally with the pad PD. Thelead-out wiring portion DWU has a function of connecting the pad PD towiring (not illustrated) formed under the pad PD. The pad PD is coveredwith a surface protective film PAS, on which an opening OP is formed toexpose part of the surface area of the pad PD. In other words, the mostpart of surface area of the pad PD is exposed through the opening OPprovided on the surface protective film PAS while the edge areaincluding the edge of the pad PD is covered with the surface protectivefilm PAS.

In this specification, the edge area of the pad PD covered with thesurface protective film PAS is defined as coating area. In FIG. 4, forexample, the coating area is dotted, and the part of surface protectivefilm PAS that covers the outer part of the step formed on the edge ofthe pad PD is also dotted. The surface protective film PAS is so formedas to cover the entire substrate on which the pad PD is formed. In FIG.4, for example, out of the surface protective film PAS, the coating areacovering the edge of the pad PD and the part of surface protective filmPAS that is formed on the outer part of the step formed on the edge ofthe pad PD are indicated as dotted areas.

A case is assumed where, for example, the resin sealing thesemiconductor chip swells or shrinks during a temperature cycle test,etc., and, for example, a stress caused by the swell or shrinkage of theresin is applied to the pad PD, as shown in FIG. 5. It is assumed inthis case, as indicated by arrows of FIG. 5, that the stress generatedin the resin sealing the semiconductor chip is applied from the edgeside ES of the semiconductor chip to the pad PD. In this case, thestress generated in the resin sealing the semiconductor chip deforms thecoating area of the pad PD covered with the surface protective film PAS.This raises a possibility of formation of “aluminum slide”, which refersto a slide of a part of the pad PD, and formation of a crack CLK on partof the coating area of the pad PD covered with the surface protectivefilm PAS.

The inventor has examined this problem and found the following threefactors to be the causes of “aluminum slide” and crack CLK. A firstfactor is that, as shown in FIG. 5, because a connecting part betweenthe pad PD and the lead-out wiring portion DWU is a right angle part,the crack CLK is formed easily on the surface protective film PAS on theconnecting part. This first factor is explained as below. For example,when the connecting part between the pad PD and the lead-out wiringportion DWU is the right angle part, a discontinuous area (seam area) ofthe surface protective film PAS covering the connecting partconcentrates on one spot. This results in concentration of a stress onthe discontinuous area with low stress resistance, which leads toformation of the crack CLK on the surface protective film PAS on theconnecting part.

The second factor is that the crack CLK is formed easily on the surfaceprotective film PAS due to the small width of the coating area of thepad PD covered with the surface protective film PAS. This second factoris assumed based on the fact that the stress resistance of the surfaceprotective film PAS is smaller in a case where the width of the coatingarea of the pad PD covered with the surface protective film PAS issmaller than a case where the width of the coating area of the pad PDcovered with the surface protective film PAS is larger.

The third factor is that “aluminum slide”, i.e., a shift of a part ofthe pad PD, and formation of the crack CLK on the surface protectivefilm PAS occur easily because the length of a line segment (part of oneside of the pad PD) perpendicular to the width of the coating area islonger than the width of the coating area of the pad PD that is coveredwith the surface protective film PAS. This third factor can beunderstood from the fact that as the length of the line segmentperpendicular to the width of the coating area becomes larger, the linesegment becomes easier to deflect due to a stress applied in thedirection perpendicular to the line segment, and warp in a greaterextent.

This specification pays attention to the above first to third factorsand describes technical concepts for suppressing the formation of the“aluminum slide” and crack CLK. A first embodiment will be described asa technical concept of providing an idea for dealing with the firstfactor that because the connecting part between the pad PD and thelead-out wiring portion DWU is the right angle part, the crack CLK isformed easily on the surface protective film PAS on the connecting part.

<Configuration of Semiconductor Chip>

FIG. 6 is an enlarged plan view of a part of the semiconductor chip CHPaccording to the first embodiment. In FIG. 6, the semiconductor chip CHPis of a rectangular having a plurality of edge sides ES that intersecteach other to form corners CNR. Inside the edge sides of thesemiconductor chip CHP, the seal ring SRG that suppresses entry of aforeign object into the semiconductor chip CHP is formed. Inside theseal ring SRG, a plurality of pads PD made mainly of aluminum (maincomponent) are arranged along the edge sides ES of the semiconductorchip CHP. Each of the plurality of pads PD is of, for example, arectangular, such as oblong. At each of the pads PD, the most part ofsurface of the pad PD is exposed through the opening OP provided on thesurface protective film PAS while the edge of the pad PD is covered withthe surface protective film PAS. The lead-out wiring portion DWU isprovided integrally with each of the pads PD, and is covered with thesurface protective film PAS. In FIG. 6, the seal ring SRG is formedinside the edge sides ES of the semiconductor chip CHP. However, a dummypattern may be provided between the edge sides ES of the semiconductorchip CHP and the seal ring SRG, where the dummy pattern suppresses theprogress of a crack, which may be formed during the dicing process, tothe interior of the semiconductor chip CHP (inside tip region). Thedummy pattern is not always necessary. Providing the dummy pattern isnevertheless preferable in order to prevent crack formation during thedicing process and improve the flattening performance of a CMP processthat is carried out upon formation of each wiring layer.

In this specification, “main component” refers to a material componentwhose content is the largest among the contents of material componentsmaking up a member (layer, film, etc.). For example, “pad PD made mainlyof aluminum (main component)” means that the pad PD contains aluminum(Al) as its material with the largest content. The term “main component”is used in this specification with the intension of, for example,expressing the fact that the pad PD is basically made of aluminum butthat does not exclude a possibility that other impurities are alsoincluded in the pad PD.

For example, the ordinary pad PD used in the semiconductor device isusually configured such that an aluminum film is held between barrierconductive films made of titanium/titanium nitrogen. In other words, thepad PD is composed of a first burrier conductive film, an aluminum filmformed on the first burrier conductive film, and a second burrierconductive film formed on the aluminum film. In this case, the pad PD iscomposed of a stacked film made up of the first burrier conductive film,the aluminum film, and the second burrier conductive film. Such a pad PDwhose major part is occupied with the aluminum film is thus referred toas “pad PD made mainly of aluminum (main component)”.

The term “aluminum film” is used in this specification as a term with abroader definition that represents not only the pure aluminum film butalso an aluminum alloy film (AlSi film) made by adding silicon toaluminum, and an aluminum alloy film (AlSiCu film) made by addingsilicon and copper to aluminum. The pad PD containing these aluminumalloy films is therefore also regarded as “pad PD made mainly ofaluminum (main component)”. Hence the phrase “pad PD made mainly ofaluminum (main component)” is used in this specification to refer to thepad PD containing the aluminum film and barrier conductive films, andalso to the pad PD whose aluminum film is an aluminum alloy film.

Features of Embodiment

The features of the first embodiment will then be described. FIG. 6illustrates a feature of the first embodiment that sloped portions SLPserving as reinforcing patterns are provided on the connecting portionsbetween the pad PD and the lead-out wiring portion DWU, respectively.According to the first embodiment, the sloped portions suppressformation of the crack CLK on the coating area where the part of pad PDthat is covered with the surface protective film PAS. The reasons forthis conclusion will be described, referring to drawings.

FIG. 7 is an enlarged view of a part of a pad PD not having the slopedportion SLP that is the feature of the first embodiment. In FIG. 7, thepad PD and the lead-out wiring portion DWU are connected integrally toeach other, and no sloped portion SLP is formed on the connecting partbetween the pad PD and the lead-out wiring portion DWU. In FIG. 7, thepad PD and the lead-out wiring portion DWU are connected perpendicularlyto each other (make a right angle) on the connecting part. For thisreason, as shown in FIG. 7, a discontinuous area SM (seam area)resulting from the deposition process, which is indicated by a dottedline, is formed concentratively at one spot on the surface protectivefilm PAS covering the connecting part between the pad PD and thelead-out wiring portion DWU. As a result, on the pad PD of FIG. 7, astress is concentrated on the discontinuous area SM with low stressresistance, which creates a condition where a crack is formed easily onthe surface protective film PAS on the connecting part between pad PDand the lead-out wiring portion DWU.

FIG. 8 is an enlarged view of a part of a pad PD having the slopedportion SLP serving as the reinforcing pattern that is the feature ofthe first embodiment. In FIG. 8, the pad PD and the lead-out wiringportion DWU are connected integrally to each other, and the slopedportion SLP is formed on the connecting part between the pad PD and thelead-out wiring portion DWU. The sloped portion SLP is formed as, forexample, a right triangle. As a result, in FIG. 8, the connection angleof the connecting part between the pad PD and the lead-out wiringportion DWU turns out to be obtuse angles each larger than a rightangle.

In this case, at the pad PD of FIG. 7, because of the absence of thesloped portion SLP, the connection angle of the connecting part betweenthe pad PD and the lead-out wiring portion DWU is a right angle formedat one spot. At the pad PD of FIG. 8, on the other hand, because of thepresence of the sloped portion SLP, the connection angle of theconnecting part between the pad PD and the lead-out wiring portion DWUis made up of obtuse angles formed at two spots. This means that at thepad PD of FIG. 7, the discontinuous area SM is formed at one spotcorresponding to the right angle at one spot, while at the pad PD ofFIG. 8, two discontinuous areas SM1 and SM2 are formed respectively attwo spots corresponding to two obtuse angles at two spots. In otherwords, at the pad PD of FIG. 7, the discontinuous area SM (seam area)resulting from the deposition process, which is indicated by the dottedline, is formed concentratively at one spot on the surface protectivefilm PAS covering the connecting part between the pad PD and thelead-out wiring portion DWU. At the pad PD of FIG. 8, on the other hand,the discontinuous areas SM1 and SM2 resulting from the depositionprocess, which are indicated by dotted lines, are formed in separationfrom each other at two spots on the surface protective film PAS coveringthe connecting part between the pad PD and the lead-out wiring portionDWU. As a result, at the pad PD having the sloped portion SLP accordingto the first embodiment, the discontinuous areas SM1 and SM2 with lowstress resistance present at two spots suppresses concentration of astress on the discontinuous area with low stress resistance present atone spot. In other words, at the pad PD having the sloped portion SLPaccording to the first embodiment, because the discontinuous areas SM1and SM2 with low stress resistance are present at two spots, the stressis distributed between the two discontinuous areas SM1 and SM2.According to the first embodiment, therefore, as a result ofdistribution of the stress between the two discontinuous areas SM1 andSM2, a stress applied to each of the discontinuous areas SM1 and SM2turned out to be smaller. Hence, according to the first embodiment, byforming the sloped portion SLP on the connecting part between the pad PDand the lead-out wiring portion DWU, formation of a crack on the surfaceprotective film PAS covering the connecting part between the pad PD andthe lead-out wiring portion DWU can be suppressed effectively. Thesemiconductor device of the first embodiment thus prevents a decline inits reliability caused by crack formation on the surface protective filmPAS. In other words, the first embodiment improves the reliability ofthe semiconductor device.

According to the first embodiment, the width (in the X direction) of thelead-out wiring portion DWU is shorter than the length of a side towhich the lead-out wiring portion DWU is connected among a plurality ofsides making up each of the plurality of pads PD, and the slopedportions SLP are provided respectively on both sides of the lead-outwiring portion DWU. According to this embodiment, therefore, by formingthe sloped portions SLP respectively on both sides of the connectionpart between the pad PD and the lead-out wiring portion DWU, crackformation on the surface protective film PAS can be suppressedeffectively on both sides of the connection part between the pad PD andthe lead-out wiring portion DWU.

For example, the pad PD, lead-out wiring portion DWU, and slopedportions SLP are formed integrally out of a film made mainly ofaluminum. As shown in FIG. 6, the lead-out wiring portion DWU isconnected to the side farthest to the edge side ES of the semiconductorchip CHP among the plurality of sides making up each of the plurality ofpads PD.

This configuration is adopted by taking into consideration the fact thatthe side farthest to the edge side ES of the semiconductor chip CHPamong the plurality of sides making up each of the plurality of pads PDis the closest to an integrated circuit region formed inside thesemiconductor chip CHP and that forming the lead-out wiring portion DWUon the side farthest to the edge side ES of the semiconductor chip CHPreduces the distance between the integrated circuit formed in theintegrated circuit region and the lead-out wiring portion DWU.Specifically, forming the lead-out wiring portion DWU on the sidefarthest to the edge side ES of the semiconductor chip CHP reduces theparasitic resistance of a wiring which connects the integrated circuitto the lead-out wiring portion DWU, thereby improves the performance ofthe semiconductor device.

The configuration of FIG. 6 in which the lead-out wiring portion DWU isprovided on the side farthest to the edge side ES of the semiconductorchip CHP is preferable in view of suppression of crack formation on thesurface protective film PAS on the connecting part between the pad PDand the lead-out wiring portion DWU. This is because that according toan examination by the inventor, in FIG. 6, for example, a stress appliedto the coating area of the side closest to the edge side ES of thesemiconductor chip CHP among the plurality of sides making up each ofthe plurality of pads PD tends to become relatively large. In FIG. 6,when the lead-out wiring portion DWU is provided on the side closest tothe edge side ES of the semiconductor chip CHP among the plurality ofsides making up each of the plurality of pads PD, the connecting partbetween the pad PD and the lead-out wiring portion DWU, on whichconnecting part a crack is formed easily, is provided on the sideclosest to the edge side ES of the semiconductor chip CHP. It ispresumed in such a case that a crack is formed easily on the surfaceprotective film PAS on the connecting part between the pad PD and thelead-out wiring portion DWU.

According to the semiconductor device of the first embodiment, in thecase of forming the lead-out wiring portion DWU on the side farthest tothe edge side ES, means for reducing a possibility of crack formation tothe minimum is also provided. Specifically, by forming the slopedportion SLP on the connecting part between the pad PD and the lead-outwiring portion DWU (first configuration), a stress is distributedbetween the two discontinuous areas SM1 and SM2 of FIG. 8. As a result,a stress applied to each of the discontinuous areas SM1 and SM2 turnsout to be smaller (stress reduction effect in the first configuration).In addition, according to the semiconductor device of the firstembodiment, by forming the lead-out wiring portion DWU on the sidefarthest to the edge side ES of the semiconductor chip CHP (secondconfiguration), a stress applied to the connecting part between the padPD and the lead-out wiring portion DWU is reduced (stress reductioneffect in the second configuration).

In this manner, according to the semiconductor device of the firstembodiment, a synergic effect created by the first and secondconfigurations effectively suppresses crack formation on the surfaceprotective film PAS on the connection part between the pad PD and thelead-out wiring portion DWU.

According to the first embodiment, the second configuration reduces theconnection distance between the integrated circuit formed in the insideregion of the semiconductor chip CHP and the lead-out wiring portionDWU, thereby offers an advantage of reducing the parasitic resistance ofthe wiring, which connects the integrated circuit to the lead-out wiringportion DWU.

The first embodiment thus offers a significant effect of improving thereliability of the semiconductor device while improving its performance.

FIG. 9 is a sectional view along an A-A line of FIG. 6. As shown in FIG.9, for example, field-effect transistors Q, which are an example ofsemiconductor elements, are formed on a semiconductor substrate 1S madeof silicon. Above the field-effect transistors Q, a fine layer FL isformed, which is composed of, for example, fine copper wiring. On thefine layer FL, a global layer GL is formed, which is composed of copperwiring wider than the copper wiring making up the fine layer FL. On theglobal layer GL, a plurality of pads PD are formed. The pads PD and theglobal layer GL are connected via the lead-out wiring portions DWU shownin FIG. 7, etc., and contact holes. As shown in FIG. 9, the pads PD areconnected electrically to the field-effect transistors Q formed on thesemiconductor substrate 1S via the global layer GL and fine layer FL.

The surface protective film PAS is so formed as to cover a plurality ofpads PD and fill a gap between the pads. The openings OP are formed onthe surface protective film PAS, and a part of the surface of each padPD is exposed from the bottom of each opening OP. The wire W made of,for example, gold wiring is connected to the surface of the pad PDexposed through the opening OP. The surface protective film PASincluding the surface of the pad PD to which the wire W is connected iscovered with, for example, the resin MR.

One of the features of the first embodiment will be described, referringto FIGS. 10 and 11. FIG. 10 is a schematic view of a configuration of aplurality of pads PD including a gap therebetween according to therelated art, and FIG. 11 is a schematic view of a configuration of aplurality of pads PD including a gap therebetween according to the firstembodiment. As shown in FIG. 10, the gap between the pads PD is filledwith the surface protective film PAS, which is composed of, for example,a silicon oxide film OXF1 formed by plasma CVD and a silicon nitridefilm SNF formed by CVD. Each pad PD is so formed as to have a thicknessranging from 1000 nm to 2000 nm, for example, a thickness of about 1600nm. The oxide silicon film OXF1 is about 200 nm in thickness, and thesilicon nitride film SNF is about 600 nm in thickness. The thickness ofthe pad PD is, therefore, larger than the sum of the thicknesses of theoxide silicon film OXF1 and the silicon nitride film SNF (1600 nm>200nm+600 nm=800 nm). As shown in FIG. 10, therefore, the gap between thepads PD is not filled completely with the surface protective film PAScomposed of the silicon oxide film OXF1 and the silicon nitride filmSNF. As a result, for example, when the resin (not illustrated) coveringthe pads PD swells and shrinks due to a temperature change during atemperature cycle test, the pads PD easily moves laterally(horizontally). This means that at the pads PD according to the relatedart of FIG. 10, a crack is formed easily on the surface protective filmPAS because of synergic factors consisting of a factor that “aluminumslide” due to a temperature change is apt to occur and tends to causeapplication of a large stress to the surface protective film PAScovering the edges of the pads PD and a factor that the surfaceprotective film PAS is thin. In other words, the configuration of thepads PD and surface protective film PAS of FIG. 10 should be improvedfurther in view of the necessity of suppressing the formation of“aluminum slide” and cracking.

According to the first embodiment, as described above, the pad PD isformed to be considerably thick. The pad PD is made thicker thanconventional pads for the main reasons that low resistance should beachieved in routing of a wiring disposed in the same layer where the padPD is disposed and that a stress created upon bringing a probe intocontact with the lower part of the pad PD by a probing inspection shouldbe eased. However, because an increase in the volume of aluminum contentcreates a situation where the above “aluminum slide” occurs easily, themeasures of the first embodiment are required.

According to the first embodiment, as shown in FIG. 11, the surfaceprotective film PAS is so formed as to completely fill the gap betweenthe pads PD. Specifically, the surface protective film PAS is composedof the silicon oxide film OXF1 formed by plasma CVD, a silicon oxidefilm OXF2 formed by high-density plasma (HDP) CVD, a silicon oxide filmOXF3 formed by plasma CVD using TEOS as a raw material, and the siliconnitride film SNF formed by CVD.

In FIG. 11, each pad PD is so formed as to have a thickness ranging from1000 nm to 2000 nm, for example, a thickness of about 1700 nm. The oxidesilicon film OXF1 is about 200 nm in thickness, the oxide silicon filmOXF2 is about 900 nm in thickness, the oxide silicon film OXF3 is about800 nm in thickness, and the silicon nitride film SNF is, for example,about 600 nm in thickness. The thickness of the pad PD is, therefore,smaller than the sum of the thicknesses of the oxide silicon films OXF1,OXF2, and OXF3 and the silicon nitride film SNF (1700 nm<200 nm+900nm+800 nm+600 nm=2500 nm). As shown in FIG. 11, therefore, the gapbetween the pads PD is filled completely with the surface protectivefilm PAS composed of the silicon oxide films OXF1, OXF2, and OXF3 andthe silicon nitride film SNF. As a result, for example, even if theresin (not illustrated) covering the pads PD swells and shrinks due to atemperature change during the temperature cycle test, the pads PD fixedfirmly by the surface protective film PAS filling the gap hardly moveslaterally (horizontally). This means that at the pad PD according to thefirst embodiment of FIG. 11, “aluminum slide” due to a temperaturechange hardly occurs and therefore a stress caused by “aluminum slide”and acting on the surface protective film PAS is eased. According to thefirst embodiment, therefore, because of the feature that the surfaceprotective film PAS is thick enough to completely fill the gap betweenthe pads PD, “aluminum slide” of the pad PD hardly occurs and a crack ishardly formed on the surface protective film PAS. In other words, theconfiguration of the pads PD and surface protective film PAS accordingto the first embodiment of FIG. 11 is superior in suppressing theformation of “aluminum slide” and cracking.

As described above, one of the features of the first embodiment is thatthe surface protective film PAS is so formed as to completely fill a gapbetween pads PD. Because of this feature, according to the firstembodiment, the formation of “aluminum slide” and cracking is suppressedeffectively, which improves the reliability of the semiconductor device.

FIG. 12 is a schematic sectional view along a B-B line of FIG. 6. Asshown in FIG. 12, a seal ring region SRR is formed inside the edge sideES of the semiconductor chip CHP, and the seal ring SRG is formed in theseal ring region SRR. A region inside the seal ring region SRR is anintegrated circuit region ICR, in which the pad PD and the lead-outwiring portion DWU formed integrally with the pad PD are formed. In thefirst embodiment, a dummy region is not formed outside the seal ringSRG. However, a dummy pattern may be formed in a location outside theseal ring SRG and closer to the edge side ES of the semiconductor chipCHP.

The seal ring SRG disclosed in this embodiment is formed by connectingmultiple wiring layers, and is connected to the semiconductor substrate1S. The seal ring SRG is connected to wells formed on the semiconductorsubstrate 1S (which connection is not illustrated) and is given a fixedpotential, such as ground potential. The dummy pattern can be formed ofthe multiple wiring layers as the seal ring SRG is. Each of the wiringlayers may be connected to or separated from each other. Different fromthe seal ring SRG, the dummy pattern is not connected to a fixedpotential node and, in many cases, is kept in a floating state.

As shown in FIG. 12, the surface protective film PAS is so formed as tocover the pad PD and lead-out wiring portion DWU formed integrallytogether. The opening OP is formed on the surface protective film PAS,and a part of the surface of the pad PD is exposed from the bottom ofthe opening OP as the lead-out wiring portion DWU is covered entirelywith the surface protective film PAS. The surface protective film PAScovers the seal ring region SRR formed outside the integrated circuitregion ICR and extends to the edge side ES of the semiconductor chipCHP.

In FIG. 12, a wiring structure and a device structure formed under thepad PD and lead-out wiring portion DWU formed in the integrated circuitregion ICR are basically the same as those shown in FIG. 9 and aretherefore not illustrated. The wire W connected to the pad PD and theresin covering the surface protective film PAS are also omitted fromFIG. 12.

<Modification>

The semiconductor device of the first embodiment is configured in theabove manner. A modification of the first embodiment will hereinafter bedescribed.

FIG. 13 is an enlarged plan view of a part of the semiconductor chip CHPof the modification. FIG. 13 shows a feature of the modification suchthat the lead-out wiring portion DWU is connected to the side closest tothe edge side ES of the semiconductor chip CHP among the plurality ofsides making up each of the plurality of pads PD and that the slopedportions SLP are provided on the connecting parts between the pad PD andthe lead-out wiring portion DWU. According to the modification, in thesame manner as in the first embodiment, crack formation on the surfaceprotective film PAS on each connecting part between the pad PD and thelead-out wiring portion DWU can be suppressed effectively.

For example, according to an examination by the inventor, a stressapplied to the coating area covering the side closest to the edge sideES of the semiconductor chip CHP among the plurality of sides making upthe pad PD tends to become relatively large. As shown in FIG. 13, whenthe lead-out wiring portion DWU is provided on the side closest to theedge side ES of the semiconductor chip CHP among the plurality of sidesmaking up the pad PD, the connecting part between the pad PD and thelead-out wiring portion DWU, on which connecting part a crack is formedeasily, is formed on the side closest to the edge side ES of thesemiconductor chip CHP. It is assumed in such a case that a crack isformed easily on the surface protective film PAS on the connecting partbetween the pad PD and the lead-out wiring portion DWU. Ordinaryreasoning thus leads to a conclusion that the configuration in which thelead-out wiring portion DWU is provided on the side closest to the edgeside ES of the semiconductor chip CHP among the plurality of sidesmaking up the pad PD is unlikely to be adopted in view of the necessityof suppressing crack formation.

According to the modification, as a result of formation of the slopedportion SLP on the connecting part between the lead-out wiring portionDWU and the pad PD, even if the lead-out wiring portion DWU is providedon the side closest to the edge side ES of the semiconductor chip CHPamong the plurality of sides making up the pad PD, formation of a crack,which develops easily on the connecting part between the pad PD and thelead-out wiring portion DWU, can be suppressed. According to themodification, because the configuration in which the sloped portion SLPis formed on the connecting part between the lead-out wiring portion DWUand the pad PD leads to suppression of crack formation on the connectingpart between the lead-out wiring portion DWU and the pad PD, theconfiguration in which the lead-out wiring portion DWU is provided onthe side closest to the edge side ES of the semiconductor chip CHP amongthe plurality of sides making up the pad PD is considered to beacceptable. Generally speaking, according to the modification,arrangement of the lead-out wiring portion DWU that is supposed to beunacceptable in view of crack prevention is rendered acceptable byadopting the technical concept of forming the sloped portion SLP on theconnecting part between the lead-out wiring portion DWU and the pad PD.

Hence, according to the modification, a degree of freedom in arrangingthe lead-out wiring portion DWU can be improved as crack formation onthe connecting part between the lead-out wiring portion DWU and the padPD is suppressed. According to the modification, therefore, animprovement in the degree of freedom in arranging the lead-out wiringportion DWU formed integrally with the pad PD leads to an improvement ina degree of freedom in an overall layout of the semiconductor chip CHP.This means that the modification allows novel layout designing notobstructed by conventional restrictions, thus improving a degree offreedom in designing the semiconductor device.

<Method of Manufacturing Semiconductor Device>

A method of manufacturing the semiconductor device according to thefirst embodiment will then be described, referring to the drawings. FIG.14 is a plan view showing a layout of a semiconductor wafer WF. As shownin FIG. 14, the semiconductor wafer WF is of an approximate disc shape,and has a plurality of chip regions CR in its internal area. In each ofthe plurality of chip regions CR, semiconductor elements, such asfield-effect transistors, and the multiple wiring layers are formed, andthe plurality of chip regions CR are demarcated by a scribe region SCR.According to the first embodiment, as shown in FIG. 14, thesemiconductor wafer (semiconductor substrate) WF having the rectangularchip regions CR and the scribe region SCR demarcating them is prepared.In the stage of preparation of the semiconductor wafer WF, in each ofthe chip regions CR of the semiconductor wafer WF, the semiconductorelements, such as field-effect transistors, are formed and the multiplewiring layers made of copper wiring are formed above the semiconductorelements by, for example, the damascene method. In the followingdescription, a process of forming pads on the uppermost layer of themultiple wiring layers in each of the chip regions CR will first bedescribed.

As shown in FIG. 15, on an interlayer insulating film IL, a stacked filmis formed, which is composed of a barrier conductive film BCF1, analuminum film AF formed on the barrier conductive film BCF1, and abarrier conductive film BCF2 formed on the aluminum film AF. The barrierconductive film BCF1 is made of, for example, a stack of a titanium filmand a titanium nitride film, and is formed by, for example, sputtering.The aluminum film AF is a film made mainly of aluminum, and is formedby, for example, sputtering. The barrier conductive film BCF2 is a filmmade of, for example, titanium nitride and is formed by, for example,sputtering, and may be made of a stacked film of titanium and titaniumnitride. For example, the barrier conductive film BCF1 is about 110 nmin thickness (titanium film of 50 nm+ titanium nitride film of 60 nm),the aluminum film AF is about 1500 nm in thickness, and the barrierconductive film BCF2 (titanium nitride film) is about 75 nm inthickness.

Subsequently, as shown in FIGS. 16A and 16B, the stacked film composedof the barrier conductive film BCF1, the aluminum film AF, and thebarrier conductive film BCF2 is patterned by photolithography andetching. By patterning the stacked film, the rectangular pad PD, thelead-out wiring portion DWU provided on the pad PD, and the slopedportions SLP provided on the connecting parts between the pad PD and thelead-out wiring portion DWU are formed integrally in each of the chipregions along the boundaries between the chip regions and the scriberegion. At this time, because the pad PD, lead-out wiring portion DWU,and sloped portions SLP are made out of the same stacked film, they arealmost equal in height.

Subsequently, as shown in FIGS. 17A and 17B, the silicon oxide film OXF1is so formed on the interlayer insulating film IL that the silicon oxidefilm OXF1 covers the pad PD, lead-out wiring portion DWU, and slopedportions SLP. The silicon oxide film OXF1 is formed by, for example,plasma CVD (Chemical Vapor Deposition) and is made into a film of about200 nm in thickness. The silicon oxide film OXF2 is then formed on thesilicon oxide film OXF1. The silicon oxide film OXF2 is formed by, forexample, high-density plasma CVD proceeding with film etching and filmdeposition simultaneously, and is made into a film of about 900 nm inthickness. The silicon oxide film OXF3 is then formed on the siliconoxide film OXF2. The silicon oxide film OXF3 is formed by, for example,plasma CVD using TEOS as a raw material, and is made into a film ofabout 800 nm in thickness. Finally, the silicon nitride film SNF isformed on the silicon oxide film OXF3. The silicon nitride film SNF isformed by, for example, CVD. In this manner, the surface protective filmPAS composed of the silicon oxide films OXF1, OXF2, and OXF3 and thesilicon nitride film SNF is so formed as to cover the pad PD, lead-outwiring portion DWU, and sloped portions SLP.

According to the first embodiment, the surface protective film PAS isthicker than the pad PD. A gap between the pads PD is therefore filledcompletely with the surface protective film PAS composed of the siliconoxide films OXF1, OXF2, and OXF3 and the silicon nitride film SNF.

Subsequently, as shown in FIGS. 18A and 18B, the opening OP that exposesa part of the pad PD is formed on the surface protective film PAS byphotolithography and etching. An opening that exposes the lead-outwiring portion DWU and the sloped portions SLP is not formed, so thatthe surfaces of the lead-out wiring portion DWU and the sloped portionsSLP are kept covered with the surface protective film PAS. Subsequently,as shown in FIGS. 19A and 19B, the surface of the pad PD exposed throughthe opening OP is etched to eliminate the barrier conductive film(titanium nitride film) formed on the surface of the pad PD exposedthrough the opening OP. As a result, the aluminum film is exposedthrough the opening OP.

In the above manner, the pads PD are formed on the uppermost layer ofthe multiple wiring layers. Specifically, FIG. 20 is a diagram of thesemiconductor chip after formation of the pads PD thereon, showing aschematic sectional view of the vicinity of the boundary area of theedge side ES (serving as a boundary in this stage). In FIG. 20, the sealring region SRR and the integrated circuit region ICR are formed insidethe scribe region SCR. The seal rings SRG are formed on the seal ringregion SRR. This seal ring SRG is formed by the process identical withthe process of forming the multi-layered wirings (not illustrated inFIG. 20) in the integrated circuit region ICR, in which the pads PD areformed on the uppermost layer.

A process to follow the above process will then be described, referringto a flowchart. FIG. 21 is a flowchart showing a flow of steps of, forexample, manufacturing the semiconductor device of the QFP packagestructure after the formation of integrated circuits on a semiconductorwafer.

An integrated circuit is formed first in each of the plurality of chipregions of the semiconductor wafer, and then the semiconductor wafer isdiced along the scribe region (S101 of FIG. 21). The semiconductor waferis thus diced into separate pieces of chip regions to acquiresemiconductor chips each carrying the integrated circuit. Eachsemiconductor chip is then mounted on a chip mounting portion formed ona lead frame (S102 of FIG. 21) and then pads and inner leads formed onthe semiconductor chip are connected by wires (S103 of FIG. 21).Subsequently, the chip mounting portion, the semiconductor chip, thewires, and the inner leads are sealed with a resin (S104 of FIG. 21).After cutting a dam formed on the lead frame (S105 of FIG. 21), thesurface of the outer leads exposed out of the resin is coated with aplating film (S106 of FIG. 21). Subsequently, marks are formed on thesurface of the resin (S107 of FIG. 21) and then the outer leadsprojecting out of the resin are formed (S108 of FIG. 21). After beingmanufacturing in this manner, the semiconductor device is subjected toan electrical characteristics test (S109 of FIG. 21). The semiconductordevice is then subjected to a temperature cycle test (5110 of FIG. 21),after which any semiconductor device evaluated as a non-defectiveproduct is shipped out.

Second Embodiment

The first embodiment has been described as the technical concept ofproviding the idea for dealing with the first factor that because theconnecting part between the pad PD and the lead-out wiring portion DWUis a right angle part, the crack CLK is formed on the surface protectivefilm PAS covering the connecting part. A second embodiment offers atechnical concept of providing an idea for dealing with the secondfactor that the crack CLK is formed easily on the surface protectivefilm PAS due to the small width of the coating area of the pad PD thatis covered with the surface protective film PAS, in addition to thetechnical concept described as the first embodiment.

FIG. 22 is an enlarged plan view of a part of the semiconductor chip CHPaccording to the second embodiment. FIG. 22 shows a feature of thesecond embodiment that the central position of the opening OP is shiftedin an inward direction (central direction) of the semiconductor chipCHP, relative to the central position of each of the plurality of padsPD.

As a result, as shown in FIG. 22, the width of a coating area CRV2 ofthe surface protective film PAS that covers the side closest to the edgeside ES of the semiconductor chip CHP among the plurality of sidesmaking up each of the plurality of pads PD is made larger than the widthof a coating area CRV1 of the surface protective film PAS that coversthe side farthest to the edge side ES of the semiconductor chip CHP.This means that the width (in the Y direction) of the coating area CRV2of the side (closest side to the edge side ES of the semiconductor chipCHP), which is most likely to be subjected to a stress caused by theswell and shrinkage of the resin (not illustrated) due to a temperaturechange among the plurality of sides making up the pad PD, can beincreased relatively. Since relatively increasing the width (in the Ydirection) of the coating area CRV2 means improving the crack resistanceto a stress, according to the semiconductor device of the secondembodiment, crack formation on the coating area CRV2 of the surfaceprotective film PAS that covers the side closest to the edge side ES ofthe semiconductor chip CHP can be suppressed. According to the secondembodiment, in addition to suppression of crack formation on theconnecting part between the lead-out wiring portion DWU and the pad PDthat is achieved by forming the sloped portion SLP on the connectingpart, an effect of suppression of crack formation on the coating areaCRV2 of the surface protective film PAS that covers the side closest tothe edge side ES of the semiconductor chip CHP is also achieved. Thetechnical concept of the second embodiment therefore provides an ideafor dealing with the above first and second factors, by which means asynergic factor consisting of the first and second factors can besuppressed effectively. Hence, the highly reliable semiconductor devicehaving superior crack resistance is provided.

As shown in FIG. 22, in the second embodiment, attention is paid to apad PD1 closest to a corner CNR of the semiconductor chip CHP among theplurality of pads PD. Specifically, as shown in FIG. 22, at the pad PD1closest to the corner CNR of the semiconductor chip CHP, the width of acoating area CRV3 of the surface protective film PAS that covers theside closest to the corner of the semiconductor chip CHP among theplurality of sides making up the pad PD1 is also made larger than thewidth of the coating area CRV1 of the surface protective film PAS thatcovers the side farthest to the edge side ES of the semiconductor chipCHP.

As a result, according to the second embodiment, at the pad PD1 closestto the corner CNR of the semiconductor chip CHP, the width (in the Ydirection) of the coating area CRV2 covering the side (side closest tothe edge side ES of the semiconductor chip CHP) where a stress caused bythe swell and shrinkage of the resin (not illustrated) due to atemperature change tends to become larger can be increased relatively.In addition, according to the second embodiment, the width of thecoating area CRV3 covering the side closest to the corner CNR, on theside where a stress tends to become larger, can also be increasedrelatively. As a result, according to the second embodiment, the crackresistance of the pad PD1 disposed closest to the corner CNR of thesemiconductor chip CHP is improved particularly.

Means for realizing the configuration in which the central position ofthe opening OP is shifted in an inward direction (central direction) ofthe semiconductor chip CHP relative to the central position of each ofthe plurality of pads PD include first means by which the size of theopening OP is reduced while the size (area) of the pad PD is maintained,and second means by which the size of the pad PD is increased while thesize (area) of the opening OP is maintained. For example, the firstmeans offers an advantage that because the size of the pad PD ismaintained, the technical concept of the second embodiment can berealized without increasing arrangement intervals (pitches) between theplurality of pads PD. This case, for example, offers an advantage thatthe technical concept of the second embodiment can be realized as anincrease in the size of the semiconductor chip is suppressed.

The second means offers an advantage that because the size of theopening OP is maintained, the technical concept of the second embodimentcan be realized without impairing the connection reliability of the wireW connected to the surface of the pad PD exposed through the opening OP.This case, for example, offers an advantage that the technical conceptof the second embodiment can be realized without affecting thereliability of the semiconductor device (particularly, the connectionreliability of the wire).

A method of manufacturing the semiconductor device according to thesecond embodiment is basically the same as the method of manufacturingthe semiconductor device according to the first embodiment. According tothe method of manufacturing the semiconductor device according to thesecond embodiment, however, in the process of forming the opening OPexposing a part of the surface of each of the plurality of pads PD onthe surface protective film PAS, the patterning by photolithography andetching is carried out in a different way. Specifically, the patterningof the opening OP is carried out so that the central position of theopening OP is shifted in an inward direction (central direction) of thechip region relative to the central position of each of the plurality ofpads PD. In other words, the patterning of the opening OP is carried outso that the width of the coating area CRV2 of the surface protectivefilm PAS that covers the side closest to the boundary among a pluralityof sides making up each of the plurality of pads PD becomes larger thanthe width of the coating area CRV1 of the surface protective film PASthat covers the side farthest to the boundary.

The patterning of the opening OP according to the second embodiment iscarried out so that at the pad PD1 closest to the corner CNR of the chipregion among the plurality of pads PD, the width of the coating areaCRV3 of the surface protective film PAS that covers the side closest tothe corner CNR of the chip region among the plurality of sides making upthe pad PD1 also becomes larger than the width of the coating area CRV1of the surface protective film PAS that covers the side farthest to theboundary.

Third Embodiment

In the first and second embodiments, the configuration example in whichthe plurality of pads PD are arranged into a single row along the edgesides ES of the semiconductor chip CHP has been described. A thirdembodiment relates to a configuration example in which the plurality ofpads PD are arranged into a plurality of rows (e.g., two rows) along theedge sides ES of the semiconductor chip CHP.

FIG. 23 is an enlarged plan view of apart of the semiconductor chip CHPaccording to the third embodiment. In FIG. 23, the plurality of pads arearranged into two rows along the edge sides ES of the semiconductor chipCHP. Specifically, the plurality of pads include a plurality of outerpads OPD arranged closer to the edge sides ES of the semiconductor chipCHP along the edge sides ES, and a plurality of inner pads IPD arrangedfarther to the edge sides ES of the semiconductor chip CHP along theedge sides ES. For example, FIG. 23 illustrates a case where two rows ofthe outer pads OPD and inner pads IPD are arranged into so-called zigzagformation. In FIG. 23, the outer pads OPD are arranged into a first rowcloser to the edge sides ES while the inner pads IPD are arranged into asecond row farther to the edge sides ES.

As shown in FIG. 23, at each of the plurality of inner pads IPD, thelead-out wiring portion DWU is provided so as to be connected to theside closest to the edge side ES of the semiconductor chip CHP among theplurality of sides making up each of the plurality of inner pads IPD,and slopes SLP (IN) are provided on the connecting parts between each ofthe plurality of inner pads IPD and the lead-out wiring portion DWU.

At each of the plurality of outer pads OPD, in contrast, the lead-outwiring portion DWU is provided so as to be connected to the sidefarthest to the edge side ES of the semiconductor chip CHP among theplurality of sides making up each of the plurality of outer pads OPD,and slopes SLP (OUT) are formed on the connecting parts between each ofthe plurality of outer pads OPD and the lead-out wiring portion DWU.

For example, the sloped portions SLP (IN) provided integrally with theinner pad IPD are identical in shape and size with the sloped portionsSLP (OUT) provided integrally with the outer pad OPD.

In this manner, according to the third embodiment, at each of the outerpads OPD and inner pads IPD arranged into zigzag formation, the slopedportions SLP (OUT) or sloped portions SLP (IN) are provided on theconnecting parts between the pad and the lead-out wiring portion DWU. Asa result, according to the third embodiment, crack formation on thecoating area where a part of the outer pad OPD is covered with thesurface protective film PAS and on the coating area where a part of theinner pad IPD is covered with the surface protective film PAS can besuppressed. In other words, the technical concept described in the firstembodiment can be applied not only to the plurality of pads PD arrangedinto a single row but also to the inner pads IPD and outer pads OPDarranged into, for example, a plurality of rows such as zigzag formationaccording to the third embodiment.

<First Modification>

In the third embodiment, the case where the sloped portions SLP (IN)provided integrally with the inner pad IPD are identical in shape andsize with the sloped portions SLP (OUT) provided integrally with theouter pad OPD, as shown in FIG. 23, has been described. A firstmodification relates to a case where the sloped portions SLP (IN) aredifferent in size from the sloped portions SLP (OUT).

FIG. 24 is an enlarged plan view of apart of the semiconductor chip CHPaccording to the first modification. As shown in FIG. 24, according tothe first modification, the size (area) of the sloped portions SLP (IN)provided integrally with the inner pad IPD is larger than the size(area) of the sloped portions SLP (OUT) provided integrally with theouter pad OPD. To put it another way, the sloped portions SLP (OUT)provided integrally with the outer pad OPD is smaller in size than thesloped portions SLP (IN) provided integrally with the inner pad IPD.

The reasons for this configuration will hereinafter be described. Theexamination by the inventor has revealed that a stress applied to thecoating area covering the side closest to the edge side ES of thesemiconductor chip CHP among the plurality of sides making up the padtends to become relatively large. Based on this knowledge, by payingattention to the inner pad IPD shown FIG. 24, it is found that the innerpad IPD is provided with the lead-out wiring portion DWU disposed on theside closest to the edge side ES of the semiconductor chip CHP among theplurality of sides making up the inner pad IPD. At the inner pad IPD,therefore, the connecting parts between the inner pad IPD and thelead-out wiring portion DWU are present on the side closest to the edgeside ES of the semiconductor chip CHP, on the side where a stress tendsto become larger. This means that at the inner pad IPD, the connectingparts between the inner pad IPD and the lead-out wiring portion DWU arepresent in the place where a stress becomes relatively large, in whichcase a crack is easily formed in the coating area of the surfaceprotective film PAS that covers the connecting parts. According to thefirst modification, to sufficiently suppress crack formation on theconnecting parts between the inner pad IPD and the lead-out wiringportion DWU, the sloped portions SLP (IN) of a large size are providedon the connecting parts. It is presumed that the sloped portions SLP(IN) of a larger size suppresses crack formation on the connecting partsbetween the inner pad IPD and the lead-out wiring portion DWU moreeffectively. For this reason, the sloped portions SLP (IN) of a largesize are formed on the connecting parts between the inner pad IPD andthe lead-out wiring portion DWU. Hence, even when a relatively largestress is applied to the connecting parts between the inner pad IPD andthe lead-out wiring portion DWU, crack formation on the connecting partscan be suppressed sufficiently.

By paying attention to the outer pad OPD shown FIG. 24, it is found thatthe outer pad OPD is provided with the lead-out wiring portion DWUdisposed on the side farthest to the edge side ES of the semiconductorchip CHP among the plurality of sides making up the outer pad OPD. Atthe outer pad OPD, therefore, the connecting parts between the outer padOPD and the lead-out wiring portion DWU are present on the side farthestto the edge side ES of the semiconductor chip CHP, on the side where astress is unlikely to become relatively larger. This means that at theouter pad IPD, the connecting parts between the outer pad OPD and thelead-out wiring portion DWU are present in the place where a stresshardly becomes large, in which case a crack is hardly formed in thecoating area of the surface protective film PAS that covers theconnecting parts. According to the first modification, in view of thefact that crack formation on the connecting parts between the outer padOPD and the lead-out wiring portion DWU is less problematic than crackformation on the connecting parts between the inner pad IPD and thelead-out wiring portion DWU, the sloped portions SLP (OUT) of a smallsize are formed on the connecting parts between the outer pad OPD andthe lead-out wiring portion DWU. It is presumed that the sloped portionsSLP (OUT) of a small size can suppress crack formation on the connectingparts between the outer pad OPD and the lead-out wiring portion DWU. Forthis reason, the sloped portions SLP (OUT) of a small size are formed onthe connecting parts between the outer pad OPD and the lead-out wiringportion DWU. Hence, the first modification realizes the configuration inwhich the sloped portions SLP (IN) provided integrally with the innerpad IPD is larger in size than the sloped portions SLP (OUT) providedintegrally with the outer pad OPD. In this configuration, crackformation on the connecting parts between the inner pad IPD and thelead-out wiring portion DWU can be suppressed and crack formation on theconnecting parts between the outer pad OPD and the lead-out wiringportion DWU can also be suppressed.

<Second Modification>

A second modification relates to a case where the sloped portions SLP(IN) are provided integrally with the inner pad IPD while no slopedportion is provided on the connecting parts between the outer pad OPDand the lead-out wiring portion DWU.

FIG. 25 is an enlarged plan view of apart of the semiconductor chip CHPaccording to the second modification. For example, as described in thefirst embodiment, the outer pad OPD is provided with the lead-out wiringportion DWU disposed on the side farthest to the edge side ES of thesemiconductor chip CHP among the plurality of sides making up the outerpad OPD. It is presumed in this case that at the outer pad OPD, a stressapplied to the connecting parts between the outer pad OPD and thelead-out wiring portion DWU is relatively small and therefore a crack ishardly formed on the coating area of the surface protective film PASthat covers the connecting parts. According to the second modification,by further taking into consideration the fact that crack formation onthe connecting parts between the outer pad OPD and the lead-out wiringportion DWU is less problematic than crack formation on the connectingparts between the inner pad IPD and the lead-out wiring portion DWU, nosloped portion is formed on the connecting parts between the outer padOPD and the lead-out wiring portion DWU. In this configuration of thesecond modification, because the sloped portions SLP (IN) are providedintegrally with the inner pad IPD, crack formation on the connectingparts between the inner pad IPD and the lead-out wiring portion DWU canbe suppressed sufficiently.

Fourth Embodiment

On the assumption that a case where the plurality of pads are arrangedinto zigzag formation along the edge sides ES of the semiconductor chipCHP is a prerequisite configuration, as in the third embodiment, afourth embodiment relates to a technical concept that further providesan idea for dealing with the second factor that a crack is formed easilyon the surface protective film PAS due to the small width of the coatingarea of the pad covered with the surface protective film PAS.

FIG. 26 is an enlarged plan view of apart of the semiconductor chip CHPaccording to the fourth embodiment. As shown in FIG. 26, according tothe fourth embodiment in which the pads are arranged into zigzagformation as the prerequisite configuration, at each of the plurality ofinner pads IPD making up the pads arranged into zigzag formation, thecentral position of the opening OP matches the central position of eachof the plurality of inner pads IPD. At each of the plurality of outerpads OPD making up the pads arranged into zigzag formation, in contrast,the central position of the opening OP is shifted toward in an inwarddirection (central direction) of the semiconductor chip CHP, relative tothe central position of each of the plurality of outer pads OPD.

As a result, as shown in FIG. 26, the width of the coating area CRV2 ofthe surface protective film PAS that covers the side closest to the edgeside ES of the semiconductor chip CHP among the plurality of sidesmaking up each of the plurality of outer pads OPD is made larger thanthe width of the coating area CRV1 of the surface protective film PASthat covers the side farthest to the edge side ES of the semiconductorchip CHP. This means that the width (in the Y direction) of the coatingarea CRV2 covering the side (side closest to the edge side ES of thesemiconductor chip CHP) most likely to be subjected to a stress causedby the swell and shrinkage of the resin (not illustrated) due to atemperature change among the plurality of sides making up the outer padOPD can be increased relatively. Since relatively increasing the width(in the Y direction) of the coating area CRV2 means improving the crackresistance of the coating area CRV2 to a stress, according to thesemiconductor device of the fourth embodiment, at the outer pad OPD,crack formation on the coating area CRV2 of the surface protective filmPAS that covers the side closest to the edge side ES of thesemiconductor chip CHP can be suppressed. According to the fourthembodiment, in the same manner as in the third embodiment, crackformation on the connecting parts can be suppressed by forming thesloped portions SLP (OUT) on the connecting parts between the outer padOPD and the lead-out wiring portion DWU and the sloped portions SLP (IN)on the connecting parts between the inner pad IPD and the lead-outwiring portion DWU. According to the fourth embodiment, because thewidth (in the Y direction) of the coating area CRV2 of the outer pad OPDcan be increased relatively, as shown in FIG. 26, crack formation on thecoating area CRV2 of the surface protective film PAS that covers theside closest to the edge side ES of the semiconductor chip CHP can alsobe suppressed.

As shown in FIG. 26, in the fourth embodiment, attention is paid to anouter pad OPD1 closest to the corner CNR of the semiconductor chip CHPamong the plurality of outer pads OPD. Specifically, as shown in FIG.26, at the outer pad OPD1 closest to the corner CNR of the semiconductorchip CHP, the width of the coating area CRV3 of the surface protectivefilm PAS that covers the side closest to the corner of the semiconductorchip CHP among the plurality of sides making up the outer pad OPD1 isalso made larger than the width of the coating area CRV1 of the surfaceprotective film PAS that covers the side farthest to the edge side ES ofthe semiconductor chip CHP.

As a result, according to the fourth embodiment, at the outer pad OPD1closest to the corner CNR of the semiconductor chip CHP, the width (inthe Y direction) of the coating area CRV2 covering the side (sideclosest to the edge side ES of the semiconductor chip CHP) where astress caused by the swell and shrinkage of the resin (not illustrated)due to a temperature change tends to become larger can be increasedrelatively. In addition, according to the fourth embodiment, the widthof the coating area CRV3 covering the side closest to the corner CNR, onthe side where a stress tends to become larger, can also be increasedrelatively. As a result, according to the fourth embodiment, the crackresistance of the outer pad OPD1 disposed closest to the corner CNR ofthe semiconductor chip CHP is improved particularly.

<Modification>

A modification of the fourth embodiment will then be described. In thefourth embodiment, in which attention is paid to the outer pads OPD, thecase of providing the idea for dealing with the second factor that acrack is formed easily on the surface protective film PAS due to thesmall width of the coating area of the outer pad OPD covered with thesurface protective film PAS has been described. This modification, inwhich attention is turned also to the inner pads IPD, relates to a casewhere the idea for dealing with the second factor is applied also to theinner pads IPD. In the fourth embodiment, because of a presumption thatthe above second factor develops into a real problem at the outer padsOPD closest to the edge side ES of the semiconductor chip CHP, the caseof applying the idea for dealing with the second factor to the outerpads OPD has been described. In this modification, although the innerpads IPD, which are more distant from the edge side ES of thesemiconductor chip CHP than the outer pads OPD, are presumed to be lessaffected by the second factor than the outer pads OPD is, a possibilityof the inner pads IPD being affected by the second factor is still takeninto consideration. In other words, according to this modification, tofurther improve the reliability of the semiconductor device, the ideafor dealing with the second factor is also applied to the inner padsIPD.

FIG. 27 is an enlarged plan view of apart of the semiconductor chip CHPaccording to this modification. As shown in FIG. 27, according to thismodification in which the pads are arranged into zigzag formation as aprerequisite configuration, at each of the plurality of outer pads OPDas well as inner pads IPD making up the pads arranged into zigzagformation, the central position of the opening OP is shifted in aninward direction (central direction) of the semiconductor chip CHP,relative to the central position of each of the plurality of inner padsIPD.

As a result, as shown in FIG. 27, the width of the coating area CRV2 ofthe surface protective film PAS that covers the side closest to the edgeside ES of the semiconductor chip CHP among the plurality of sidesmaking up each of the plurality of inner pads IPD is made larger thanthe width of the coating area CRV1 of the surface protective film PASthat covers the side farthest to the edge side ES of the semiconductorchip CHP. This means that the width (in the Y direction) of the coatingarea CRV2 covering the side (side closest to the edge side ES of thesemiconductor chip CHP) most likely to be subjected to a stress causedby the swell and shrinkage of the resin (not illustrated) due to atemperature change among the plurality of sides making up the inner padIPD can be increased relatively. Since relatively increasing the width(in the Y direction) of the coating area CRV2 means improving the crackresistance of the coating area CRV2 to a stress, according to thesemiconductor device of this modification, at the inner pad IPD, crackformation on the coating area CRV2 of the surface protective film PASthat covers the side closest to the edge side ES of the semiconductorchip CHP can be suppressed.

As shown in FIG. 27, in this modification, attention is paid to an innerpad IPD1 closest to the corner CNR of the semiconductor chip CHP amongthe plurality of inner pads IPD. Specifically, as shown in FIG. 27, atthe inner pad IPD1 closest to the corner CNR of the semiconductor chipCHP, the width of the coating area CRV3 of the surface protective filmPAS that covers the side closest to the corner of the semiconductor chipCHP among the plurality of sides making up the inner pad IPD1 is alsomade larger than the width of the coating area CRV1 of the surfaceprotective film PAS that covers the side farthest to the edge side ES ofthe semiconductor chip CHP.

As a result, according to the this modification, at the inner pad IPD1closest to the corner CNR of the semiconductor chip CHP, the width (inthe Y direction) of the coating area CRV2 covering the side (sideclosest to the edge side ES of the semiconductor chip CHP) where astress caused by the swell and shrinkage of the resin (not illustrated)due to a temperature change tends to become larger can be increasedrelatively. In addition, according to this modification, the width ofthe coating area CRV3 covering the side closest to the corner CNR, onthe side where a stress tends to become larger, can also be increasedrelatively. As a result, according to this modification, the crackresistance of the inner pad IPD1 disposed closest to the corner CNR ofthe semiconductor chip CHP is improved particularly.

In this manner, according to this modification, the idea for dealingwith the second factor is applied not only to the outer pads OPD, butalso to the inner pads IPD. As a result, according to this modification,at the plurality of outer pads OPD as well as inner pads IPD arrangedinto zigzag formation, their crack resistance against the first andsecond factors can be improved, which further improves the reliabilityof the semiconductor device.

Fifth Embodiment

A fifth embodiment relates to a technical concept of providing an ideafor dealing with the above third factor. The fifth embodiment is,therefore, described as the idea for solving the problem that “aluminumslider”, i.e., a shift of a part of the pad PD, and formation of thecrack CLK on the surface protective film PAS occur easily because thelength (in the X direction) of a line segment (part of one side of thepad PD) perpendicular to the width of the coating area is longer thanthe width (in the Y direction) of the coating area of the pad PD coveredwith the surface protective film PAS.

FIG. 28 is a plan view schematically showing a configuration of the padPD according to a fifth embodiment. In FIG. 28, the lead-out wiringportion DWU is provided integrally with the pad PD. The lead-out wiringportion DWU is provided such that the width (in the X direction) of thelead-out wiring portion DWU is smaller than the length of a side towhich the lead-out wiring portion DWU is connected among the pluralityof sides making up the pad PD and that the central position of the widthof the lead-out wiring portion DWU is shifted relative to the centralposition of the side to which the lead-out wiring portion DWU isconnected among the plurality of sides making up the pad PD.

At the pad PD of the fifth embodiment configured in such a manner, asshown in FIG. 28, on one side of the lead-out wiring portion DWU, thelength of a line segment not in contact with the lead-out wiring portionDWU and making up a part of the side to which the lead-out wiringportion DWU is connected is larger (longer line segment side on the leftof the lead-out wiring portion DWU of FIG. 28). On the other side of thelead-out wiring portion DWU, the length of a line segment not in contactwith the lead-out wiring portion DWU and making up a part of the side towhich the lead-out wiring portion DWU is connected is smaller (shorterline segment side on the right of the lead-out wiring portion DWU ofFIG. 28).

At the pad PD of the fifth embodiment configured in such a manner, theside warps more heavily on the longer line segment side because of theswell and shrinkage of the resin (not illustrated) due to a temperaturechange. This increases a possibility of the formation of “aluminumslide” and cracking on the longer line segment side.

According to the fifth embodiment in which sloped portions are providedon both sides of the lead-out wiring portion DWU, a sloped portion SLP1provided on one side (longer line segment side) of the lead-out wiringportion DWU is made asymmetric in shape with a sloped portion SLP2provided on the other side (shorter line segment side) of the lead-outwiring portion DWU.

Specifically, as shown in FIG. 28, the sloped portion SLP1 provided onone side (longer line segment side) of the lead-out wiring portion DWUis larger in size than the sloped portion SLP2 provided on the otherside (shorter line segment side) of the lead-out wiring portion DWU. Forexample, as shown in FIG. 28, the sloped portion SLP1 formed on one side(longer line segment side) of the lead-out wiring portion DWU is of atrapezoid, while the sloped portion SLP2 formed on the other side(shorter line segment side) of the lead-out wiring portion DWU is of atriangle.

In this manner, because of the larger size of the sloped portion SLPformed on the long line segment side on which the side is likely to warpmore heavily, warping on the long line segment side is suppressed. As aresult, according to the fifth embodiment, the formation of “aluminumslide” and cracking caused by warping on the long line segment side canbe suppressed effectively.

An examination by the inventor has led to a finding that when b1/a1<3 issatisfied, as shown in FIG. 28, where a1 denotes the width (in the Ydirection) of the coating area of the surface protective film PAS thatcovers the side to which the lead-out wiring portion DWU is connectedamong the plurality of sides making up the pad PD and b1 denotes thewidth (in the X direction) of the coating area of the surface protectivefilm PAS, a warp of the side of the pad PD caused by a stress due to theswell and shrinkage of the resin can be suppressed sufficiently. For thesame reason, it is also preferable that b2/a2<3 be satisfied, where a2denotes the height (in the Y direction) of the sloped portion SLP1 asthe trapezoid and b2 denotes the length of the bottom side of the slopedportion SLP1 as the trapezoid. It is more preferable that(b2/a2)+(b1/a1))<3 be satisfied.

<First Modification>

As described in the fifth embodiment, in view of the necessity ofpreventing the formation of “aluminum slide” and cracking caused bywarping on the long line segment side, it is preferable to make thesloped portion SLP1 provided on one side (longer line segment side) ofthe lead-out wiring portion DWU larger in size than the sloped portionSLP2 provided on the other side (shorter line segment side) of thelead-out wiring portion DWU.

However, shaping the sloped portion SLP1 into a trapezoid and the slopedportion SLP2 into a triangle is merely one example. For example, asshown in FIG. 29, the sloped portion SLP1 formed on one side (longerline segment side) of the lead-out wiring portion DWU may be shaped intoa first triangle and the sloped portion SLP2 formed on the other side(shorter line segment side) of the lead-out wiring portion DWU may beshaped into a second triangle.

In such a case, in view of the necessity of surely preventing theformation of “aluminum slide” and cracking caused by warping on thelonger line segment side, it is preferable that b1/a1<3 be satisfied,where a1 denotes the width (in the Y direction) of the coating area ofthe surface protective film PAS that covers the side to which thelead-out wiring portion DWU is connected among the plurality of sidesmaking up the pad PD and b1 denotes the width (in the X direction) ofthe coating area of the surface protective film PAS. For the samereason, it is also preferable that b2/a2<3 be satisfied, where a2denotes the height (in the Y direction) of the sloped portion SLP1 asthe first triangle and b2 denotes the length (in the X direction) of thebottom side of the sloped portion SLP1 as the first triangle. It is morepreferable that (b2/a2)+(b1/a1)<3 be satisfied.

<Second Modification>

The techniques disclosed referring to FIGS. 28 and 29 may be applied tothe configurations of FIGS. 23, 24, and 25 described in the thirdembodiment. Specifically, the above sloped portions SLP1 and SLP2 may beformed on the first and second rows of pads arranged into zigzagformation, as in the case of FIG. 23. The sloped portions SLP1 and SLP2formed on the pads on the second row of the zigzag formation may be madelarger than the sloped portions SLP1 and SLP2 formed on the pads on thefirst row of the zigzag formation, as in the case of FIG. 24. The slopedportions SLP1 and SLP2 may be formed only on the pads on the second rowof the zigzag formation and not formed on the pads on the first row, asin the case of FIG. 25. The techniques disclosed referring to FIGS. 28and 29 may be applied to the configuration of the above fourthembodiment.

Sixth Embodiment

On the assumption that the presence of a plurality of lead-out wiringportions DWU provided integrally with the pad PD is a prerequisiteconfiguration, a sixth embodiment relates to a case where a technicalconcept of providing an idea for dealing with the first factor isapplied to this prerequisite configuration.

FIG. 30 is an enlarged plan view of a part of the semiconductor chip CHPaccording to the sixth embodiment. In FIG. 30, for example, among theplurality of outer pads OPD and inner pads IPD arranged into zigzagformation, an outer pad OPD2 included in the row of outer pads OPD isprovided with a lead-out wiring portion DWU1 and a lead-out wiringportion DWU2 that are provided integrally with the outer pad OPD2. Thisis an example of a layout adopted for ensuring a sufficient amount ofcurrent flowing through the outer pad OPD2. For example, when currentflowing through the outer pad OPD2 is so large that the single lead-outwiring portion DWU1 cannot handle current inflow to the outer pad OPD2,the lead-out wiring portions DWU1 and DWU2 are provided integrally withthe outer pad OPD2 in order to handle large current inflow. The lead-outwiring portion DWU2 has a contact (not illustrated) connected to alower-layer wiring as the lead-out wiring portion DWU1 does and istherefore connected electrically to field-effect transistors Q disposedin the integrated circuit region.

Such a lead-out wiring portion DWU2 is effective in terms of reducing achip area when no space for disposing a pad exists between two outerpads OPD or two pads OPD having the same functions related to powersupply, etc., need to be lined up next to each other.

Specifically, as shown in FIG. 30, the outer pad OPD2 is of an oblong,and the plurality of lead-out wiring portions connected to the outer padOPD2 are made up of the lead-out wiring portion DWU1 connected to ashort side of the outer pad OPD2 and the lead-out wiring portion DWU2connected to a long side of the outer pad OPD2. In this case, the slopedportions SLP (OUT) are provided on the connecting parts between theouter pad OPD2 and the lead-out wiring portion DWU1 and are alsoprovided on the connecting parts between the outer pad OPD2 and thelead-out wiring portion DWU2.

At the outer pad OPD2 of the sixth embodiment configured in such amanner, crack formation can be suppressed on the connecting partsbetween the outer pad OPD2 and the lead-out wiring portion DWU1 as wellas on the connecting parts between the outer pad OPD2 and the lead-outwiring portion DWU2.

While the case of forming both lead-out wiring portions DWU1 and DWU2 onthe outer pad OPD2 is described in the sixth embodiment, this is not theonly case. For example, the same effect as described above is achievedeven in the case of forming only the lead-out wiring portion DWU2 on theouter pad OPD2.

While the case of zigzag arrangement of the pads is described in thesixth embodiment, the technical concept of the sixth embodiment can beapplied also to the case where the pads are arranged into a single rowas in the first and second embodiments. In other words, the techniquedisclosed in the sixth embodiment can be applied also to the above firstto fifth embodiments.

Seventh Embodiment

A seventh embodiment relates to a case where the position of the openingof the silicon nitride film SNF making up the surface protective filmPAS shown in FIG. 11 is changed.

FIG. 31 is a plan view of the pad PD, and FIG. 32 is a sectional view ofthe pad PD. According to the seventh embodiment, the silicon oxide filmsOXF1, OXF2, and OXF3 are formed and then patterning using a photoresistfilm as a mask is performed to form an opening OP1. The barrierconductive film BCF2 is also etched in the same process, as a result ofwhich the aluminum film AF is exposed through the opening OP1.Subsequently, the silicon nitride film SNF is formed and is patternedseparately to form an opening OP2 inside the opening OP1.

According to the seventh embodiment, in the opening OP1, the side facesof the silicon oxide films OXF1, OXF2, and OXF3 and barrier conductivefilm BCF2 can be covered with the silicon nitride film SNF. When thebarrier conductive film BCF2 is made of titanium nitride, therefore,oxidation of the titanium nitride is prevented. Oxidation of thetitanium nitride increases its volume, and the more voluminous titaniumnitride applies a stress to the surface protective film PAS overlaid onthe titanium nitride. This raises a concern that a crack is easilyformed on the silicon nitride film SNF. To eliminate this concern,according to the seventh embodiment, the side face of the barrierconductive film BCF2 is covered with the silicon nitride film SNF, inwhich case crack formation is prevented further effectively.

The technique disclosed in the seventh embodiment can obviously beapplied to the above first to sixth embodiments, in which case theopening OP2 of the seventh embodiment is equivalent to the opening OP ofthe first to sixth embodiments.

In the foregoing, the invention made by the inventors of the presentinvention has been concretely described based on the embodiments.However, it is needless to say that the present invention is not limitedto the foregoing embodiments and various modifications and alterationscan be made within the scope of the present invention.

The above embodiments include the following embodiments.

(Note 1)

A semiconductor device comprising a rectangular semiconductor chip,

wherein the semiconductor chip includes:

(a) a plurality of pads arranged along an edge side of the semiconductorchip;

(b) a lead-out wiring portion provided on each of the plurality of pads;and

(c) a sloped portion provided on a connecting part between each of theplurality of pads and the lead-out wiring portion,

wherein a width of the lead-out wiring portion is smaller than a lengthof aside to which the lead-out wiring portion is connected among aplurality of sides making up each of the plurality of pads,

a central position of the width of the lead-out wiring portion isshifted relative to a central position of the side to which the lead-outwiring portion is connected among the plurality of sides making up eachof the plurality of pads.

(Note 2)

The semiconductor device according to note 1,

wherein the sloped portions are provided on both sides of the lead-outwiring portion, respectively.

(Note 3)

The semiconductor device according to note 2,

wherein the sloped portion formed on one side of the lead-out wiringportion is asymmetric in shape with the sloped portion formed on theother side of the lead-out wiring portion.

(Note 4)

The semiconductor device according to note 3,

wherein on one side of the lead-out wiring portion, a length of a linesegment not in contact with the lead-out wiring portion and making up apart of a side to which the lead-out wiring portion is connected islarger,

on the other side of the lead-out wiring portion, a length of a linesegment not in contact with the lead-out wiring portion and making up apart of the side to which the lead-out wiring portion is connected issmaller, and

the sloped portion provided on the one side of the lead-out wiringportion is larger in size than the sloped portion provided on the otherside of the lead-out wiring portion.

(Note 5)

The semiconductor device according to note 4,

wherein the sloped portion provided on one side of the lead-out wiringportion is of a trapezoid, while the sloped portion provided on theother side of the lead-out wiring portion is of a triangle.

(Note 6)

The semiconductor device according to note 5, comprising:

(d) a surface protective film covering each of the plurality of pads,the lead-out wiring portion, and the sloped portion,

wherein the surface protective film has an opening that exposes a partof a surface of each of the plurality of pads, and

b2/a2<3 is satisfied, where a2 denotes a height of the trapezoid and b2denotes a length of a bottom side of the trapezoid.

(Note 7)

The semiconductor device according to note 4,

wherein the sloped portion provided on one side of the lead-out wiringportion is of a first triangle and the sloped portion provided on theother side of the lead-out wiring portion is of a second triangle.

(Note 8)

The semiconductor device according to note 7, comprising:

(d) a surface protective film covering each of the plurality of pads,the lead-out wiring portion, and the sloped portion, wherein the surfaceprotective film has an opening that exposes a part of a surface of eachof the plurality of pads, and

b2/a2<3 is satisfied, where a2 denotes a height of the first triangleand b2 denotes a length of a bottom side of the first triangle.

(Note 9)

A semiconductor device comprising a rectangular semiconductor chip,

the semiconductor chip includes:

(a) a plurality of pads arranged along an edge side of the semiconductorchip;

(b) a lead-out wiring portion provided on each of the plurality of pads;and

(c) a sloped portion provided on a connecting part between each of theplurality of pads and the lead-out wiring portion,

wherein a plurality of lead-out wiring portions are connected to a firstpad among the plurality of pads, and the sloped portion is provided oneach of connecting parts of each of the plurality of lead-out wiringportions connected to the first pad.

(Note 10)

The semiconductor device according to note 9,

wherein each of the plurality of pads is of an oblong, and

the plurality of lead-out wiring portions connected to the first padinclude a first lead-out wiring portion connected to a short side of thefirst pad and a second lead-out wiring portion connected to a long sideof the first pad.

(Note 11)

A method of manufacturing a semiconductor device, comprising:

(a) a step of preparing a semiconductor substrate having rectangularchip regions and a scribe region demarcating the chip regions; and

(b) a step of forming a plurality of rectangular pads, a lead-out wiringportion provided on each of the plurality of pads, and a sloped portionprovided on a connecting part between each of the plurality of pads andthe lead-out wiring portion, in each of the chip regions alongboundaries between the chip regions and the scribe region.

(Note 12)

The method of manufacturing a semiconductor device according to note 11,comprising:

(c) a step of forming a surface protective film covering the pluralityof pads, the lead-out wiring portion, and the sloped portion;

(d) a step of forming an opening on the surface protective film, theopening exposing a part of a surface of each of the plurality of pads;

(e) a step of dicing the semiconductor substrate along the scribe regionto acquire semiconductor chips, following the step (d);

(f) a step of connecting a wire to a surface of each of the plurality ofpads exposed through the opening, following the step (e); and

(g) a step of sealing the semiconductor chips, following the step (f).

(Note 13)

The method of manufacturing a semiconductor device according to note 12,comprising:

a step of conducting a temperature cycle test, following the step (g).

(Note 14)

The method of manufacturing a semiconductor device according to note 12,

wherein the opening is formed at the step (d) such that a centralposition of the opening is shifted toward in an inward direction of thechip region, relative to a central position of each of the plurality ofpads.

(Note 15)

The method of manufacturing a semiconductor device according to note 12,

wherein the opening is formed at the step (d) such that a width of acoating area of the surface protective film that covers a side closestto the boundary among a plurality of sides making up each of theplurality of pads is made larger than a width of a coating area of thesurface protective film that covers a side farthest to the boundary.

(Note 16)

The method of manufacturing a semiconductor device according to note 15,

wherein the opening is formed at the step (d) such that at a first padclosest to a corner of the chip region among the plurality of pads, awidth of a coating area of the surface protective film that covers aside closest to the corner of the chip region among a plurality of sidesmaking up the first pad is also made larger than a width of a coatingarea of the surface protective film that covers a side farthest to theboundary.

What is claimed is:
 1. A semiconductor device comprising a rectangularsemiconductor chip, wherein the semiconductor chip includes: (a) aplurality of pads arranged along an edge side of the semiconductor chip;(b) a lead-out wiring portion provided on each of the plurality of pads;and (c) a sloped portion provided on a connecting part between each ofthe plurality of pads and the lead-out wiring portion.
 2. Thesemiconductor device according to claim 1, wherein each of the pluralityof pads, the lead-out wiring portion, and the sloped portion are formedintegrally together.
 3. The semiconductor device according to claim 1,wherein a width of the lead-out wiring portion is smaller than a lengthof a side to which the lead-out wiring portion is connected among aplurality of sides making up each of the plurality of pads.
 4. Thesemiconductor device according to claim 3, wherein the sloped portionsare formed on both sides of the lead-out wiring portion, respectively.5. The semiconductor device according to claim 1, wherein the lead-outwiring portion is connected to a side farthest to the edge side of thesemiconductor chip among a plurality of sides making up each of theplurality of pads.
 6. The semiconductor device according to claim 1,wherein the lead-out wiring portion is connected to a side closest tothe edge side of the semiconductor chip among a plurality of sidesmaking up each of the plurality of pads.
 7. The semiconductor deviceaccording to claim 1, comprising: (d) a surface protective film coveringeach of the plurality of pads, the lead-out wiring portion, and thesloped portion, wherein the surface protective film has an opening thatexposes a part of a surface of each of the plurality of pads.
 8. Thesemiconductor device according to claim 7, wherein a central position ofthe opening is shifted in an inward direction of the semiconductor chip,relative to a central position of each of the plurality of pads.
 9. Thesemiconductor device according to claim 7, wherein a width of a coatingarea of the surface protective film that covers aside closest to theedge side of the semiconductor chip among a plurality of sides making upeach of the plurality of pads is larger than a width of a coating areaof the surface protective film that covers a side farthest to the edgeside of the semiconductor chip.
 10. The semiconductor device accordingto claim 9, wherein at a first pad closest to a corner of thesemiconductor chip among the plurality of pads, a width of a coatingarea of the surface protective film that covers a side closest to thecorner of the semiconductor chip among a plurality of sides making upthe first pad is also larger than a width of a coating area of thesurface protective film that covers a side farthest to the edge side ofthe semiconductor chip.
 11. The semiconductor device according to claim1, wherein the plurality of pads include: (a1) a plurality of outer padslocated closer to the edge side of the semiconductor chip and disposedalong the edge side; and (a2) a plurality of inner pads located fartherto the edge side of the semiconductor chip and disposed along the edgeside.
 12. The semiconductor device according to claim 11, wherein at theplurality of inner pads, the lead-out wiring portion is provided so asto be connected to a side closest to the edge side of the semiconductorchip among a plurality of sides making up each of the plurality of innerpads, and the sloped portion is provided on a connecting part betweeneach of the plurality of inner pads and the lead-out wiring portion. 13.The semiconductor device according to claim 12, wherein at the pluralityof outer pads, the lead-out wiring portion is provided so as to beconnected to a side farthest to the edge side of the semiconductor chipamong a plurality of sides making up each of the plurality of outerpads.
 14. The semiconductor device according to claim 13, wherein thesloped portion is not provided on a connecting part between each of theplurality of outer pads and the lead-out wiring portion.
 15. Thesemiconductor device according to claim 13, wherein the sloped portionis provided on a connecting part between each of the plurality of outerpads and the lead-out wiring portion.
 16. The semiconductor deviceaccording to claim 15, wherein the sloped portion provided on aconnecting part between each of the plurality of outer pads and thelead-out wiring portion is smaller in size than the sloped portionprovided on a connecting part between each of the plurality of innerpads and the lead-out wiring portion.
 17. The semiconductor deviceaccording to claim 11, comprising: (d) a surface protective filmcovering each of the plurality of pads, the lead-out wiring portion, andthe sloped portion, wherein the surface protective film has an openingthat exposes a part of a surface of each of the plurality of pads, andat each of the plurality of outer pads, a central position of theopening is shifted in an inward direction of the semiconductor chiprelative to a central position of each of the plurality of outer pads,while at each of the plurality of inner pads, a central position of theopening matches a central position of each of the plurality of innerpads.
 18. The semiconductor device according to claim 11, comprising:(d) a surface protective film covering each of the plurality of pads,the lead-out wiring portion, and the sloped portion, wherein the surfaceprotective film has an opening that exposes a part of a surface of eachof the plurality of pads, a width of a coating area of the surfaceprotective film that covers a side closest to the edge side of thesemiconductor chip among a plurality of sides making up each of theplurality of outer pads is larger than a width of a coating area of thesurface protective film that covers a side farthest to the edge side ofthe semiconductor chip, and at a first outer pad closest to a corner ofthe semiconductor chip among the plurality of outer pads, a width of acoating area of the surface protective film that covers a side closestto the corner of the semiconductor chip among a plurality of sidesmaking up the first outer pad is also larger than a width of a coatingarea of the surface protective film that covers a side farthest to theedge side of the semiconductor chip.
 19. The semiconductor deviceaccording to claim 18, wherein a width of a coating area of the surfaceprotective film that covers a side closest to the edge side of thesemiconductor chip among a plurality of sides making up each of theplurality of inner pads is larger than a width of a coating area of thesurface protective film that covers a side farthest to the edge side ofthe semiconductor chip, and at a first inner pad closest to a corner ofthe semiconductor chip among the plurality of inner pads, a width of acoating area of the surface protective film that covers a side closestto the corner of the semiconductor chip among a plurality of sidesmaking up the first inner pad is also larger than a width of a coatingarea of the surface protective film that covers a side farthest to theedge side of the semiconductor chip.
 20. A method of manufacturing asemiconductor device, comprising: (a) a step of preparing asemiconductor substrate having rectangular chip regions and a scriberegion demarcating the chip regions; and (b) a step of forming aplurality of rectangular pads, a lead-out wiring portion disposed oneach of the plurality of pads, and a sloped portion disposed on aconnecting part between each of the plurality of pads and the lead-outwiring portion, in each of the chip regions along boundaries between thechip regions and the scribe region.